1. Technical Field
This specification relates generally to piezoelectric transducers.
2. Background Art
A piezoelectric transducer includes a piezoelectric element capable of converting electrical energy into mechanical energy (e.g., sound or ultrasound energy), and vice versa. Thus, a piezoelectric transducer can serve both as a transmitter of mechanical energy and a sensor of impinging mechanical energy.
An ultrasonic piezoelectric transducer device can include a piezoelectric vibrating element that vibrates at a high frequency in response to a time-varying driving voltage, and generates a high frequency pressure wave in a propagation medium (e.g., air, water, or tissue) in contact with an exposed outer surface of the vibrating element. This high frequency pressure wave can propagate into other media. The same vibrating element can also receive reflected pressure waves from the propagation media, and convert the received pressure waves into an electrical signal. The electrical signal can be processed in conjunction with the driving voltage signal to obtain information on variations of density or elastic modulus in the propagation media.
An ultrasonic piezoelectric transducer device can include an array of piezoelectric vibrating elements, each vibrating element can be individually controlled with a respective driving voltage and/or pulse width and time delay, such that a pressure wave having a desired direction, shape, and focus can be created in the propagation medium by the array of vibrating elements collectively, and information on the variations of density or elastic modulus in the propagation media can be more accurately and precisely ascertained based on the reflected and/or refracted pressure waves captured by the array of piezoelectric vibrating elements.